Electronic equipment often uses cables to attach to other electronic equipment, or to attach to transducers or other such electrodes, sensors or devices. In order to monitor such equipment and verify proper operation, it is sometimes required to detect that required cables have been attached. It is further sometimes required to detect the type of cables that have been attached.
For example, in the medical field, a patient monitoring system is often used in a healthcare facility in order to obtain information regarding selected physiological parameters of a patient. In such a system a multi-conductor cable is placed in the vicinity of the patient and patient data is gathered by one or more suitable sensors. The multi-conductor cable is plugged into or otherwise interconnected to the patient monitor so that that the gathered data may be usefully displayed. In order to ensure the integrity of the displayed data and/or to properly configure the displayed data, some means is needed to detect and verify the actual presence of the cable and the associated cable type. Among other benefits, detection of the type of cable would allow the patient monitoring system to allocate display area only for the particular physiological parameters that are obtained for the particular cable type.
In order to provide cable detection, known cable interconnection systems typically include one or more conductors that are dedicated to the cable detection function. Because the additional conductors reside within the cable, additional pins are required at the cable connector. However, in some situations the inclusion of additional conductors and connector pins may be either undesirable or impossible. For example, the additional pins needed within the connector may not be available. Other known systems use a mechanical switch or sensor to determine the presence of a cable. However, mechanical switches are cumbersome, expensive and eventually unreliable. In either case, in order to identify the type of cable that has been detected, one system requires that a separate coding resistor, having a standardized value, be included within the cable. Both types of known cable detection systems are not easily retrofitted into existing connector forms. A cable detection system constructed according to the principles of the present invention addresses these deficiencies and related problems.